Method and apparatus for dry mixing

ABSTRACT

A method and apparatus for mixing fine powdered material with other dry material, without creating an objectionable dusty environment, which consists in placing the dry powdered material in a pan, carefully inserting the filled pan into the mouth of a rotatable mixing drum by sliding a pair of coaxial lugs that project from opposite sides of the pan along parallel tracks fixed to the walls of the drum and then by means of pointed screws passing through opposite walls of the drum to engage in sockets in the lugs, pivotally connect the pan to the drum so that during rotation of the drum after its mouth has been tightly closed, the pan swings around the axis of its pivotal connection with the drum and spills the fine powdered material onto the other material in the drum.

limited States Patent [1 1 Krull METHOD AND APPARATUS FOR DRY MIXING [76] Inventor: Frank B. Krull, c/o The Krull Company, Highway M-35 lngallston, P.O. Box 55,

Menominee, Mich. 49858 22 Filed: Nov. 29, 1972 21 Appl. No.: 310,409

[52] US. Cl 259/148, 259/57, 259/177 R [51] Int. Cl. B66d 1/76 [58] Field of Search... 259/175, 176, 177 R, 177 A, 259/3, 14, 30, 57

[ 1 Feb. 19, 1974 Primary Examiner-Robert W. Jenkins [57] ABSTRACT A method and apparatus for mixing fine powdered material with other dry material, without creating an objectionable dusty environment, which consists in placing the dry powdered material in a pan, carefully inserting the filled pan into the mouth of a rotatable mixing drum by sliding a pair of coaxial lugs that project from opposite sides of the pan along parallel tracks fixed to the walls of the drum and then by means of pointed screws passing through opposite walls of the drum to engage in sockets in the lugs, pivotally connect the pan to the drum so that during rotation of the drum after its mouth has been tightly closed, the pan swings around the axis of its pivotal connection with the drum and spills the fine powdered material onto the other material in the drum.

9 Claims, 5 Drawing Figures PAIENTED FEB I 91974 sum 2 0r 3 METHOD AND APPARATUS FOR DRY MIXING This invention relates to dry mixing of different materials including fine lightweight pulverized material, such as very fine aluminum powder. Dry mixing of such fine pulverized and often fluffy materials with other materials has long been a problem. In all known prior methods and apparatus for doing so, an extremely dusty condition or environment was inevitable, which was not only unpleasant, but also a health hazard.

By contrast, the present invention enables the dry powdered material to be introduced into a mixing drum containing the material with which it is to be admixed, without in anywise disturbing the powdered material so that the heretofore dusty conditions are avoided.

More specifically, the invention accomplishes its pur pose through the provision of a pan to hold the powdered material, and structure in the mixing drum to slidably support the pan for bodily insertion into the drum, and other means for pivotally connecting the pan with the drum, so that after the mouthof the drum is tightly closed, rotation of the drum causes the pan to revolve and spill its contents of dry powdered material onto the other material in the drum for admixture in the closed drum as the drum turns.

With these observationsand objectives in mind, the

manner in which the invention achieves its purpose will be appreciated from the following description and the accompanying drawings, which exemplify the invention, it being understood that changes may be made in the precise method of practicing the invention and in the specific apparatus disclosed herein without departing from the essentials of the invention set forth in the appended claims. The accompanying drawings illustrate one complete example of an embodiment of the invention constructed according to the best mode so far devised for the practical application of the principles thereof, and in which:

FIG. 1 is a side view of the mixing apparatus of this invention;

FIG. 2 is an end view of the mixing apparatus;

FIG. 3 is a top view of the charging and discharging end portion of the mixing apparatus, with a part thereof broken away and in section;

FIG. 4 is a perspective view of certain major parts of the improved mixing apparatus, showing the same separated; and

FIG. 5 is a detail sectional view taken on the plane of the line 5-5 in FIG. 3.

Referring to the drawings, the numeral 6 indicates generally a more or less conventional mixing machine comprising a tub-like drum 7 mounted in the usual manner 'for rotation about its central axis and for endwise tilting motion in a frame 8 which has wheels 9 to facilitate transporting the machine. A motor 10 provides a power source for imparting rotation to the mixing drum. The motor is drivingly connected with the drum through reduction transmission means 11 which drives a pinion 12 that meshes with a ring gear 13 encircling and fixed to the mixing drum. Another motor 14, acting through reduction transmission means 15 is provided to tilt the drum.

The drum has a single charging and discharging opening or mouth 16 defined by a cylindrical wall 17, and mixing blades 18 projecting inwardly from its side wall to promote admixture of the drum contents during rotation of the drum. When only ordinary material is to be mixed, that material can be introduced into the drum in the customary way, with the drum in an upright position, i.e. with its mouth facing upward, but when light pulverized material is to be included in the admixture, the drum is positioned with its axis substantially horizontal.

With the drum thus positioned, a pan l9 filled with the fine powdered material is carefully slid into position in the open end portion of the drum. To enable this to be done without disturbing the powdered material, diametrically opposite coaxial lugs or bosses 20 projecting from the side wall 21 of the pan are inserted into the open ends ofa pair of parallel tracks 22 that are formed in the cylindrical wall 17 of the drum, and then the pan is gently pushed towards the inner end of the tracks without allowing it to tiltor'tip.

The tracks 22 have their inner ends closed to provide stops 23 to limit insertion of the pan into the drum, these stops being so located that when the lugs or bosses contact them no portion of the pan protrudes from the mouth of the drum. Also, when the lugs or bosses 20 engage the stops, sockets 24 in the ends of the lugs or bosses align with coaxial pointed cap screws 25 that project through the wall of the drum to have their pointed ends enter the sockets upon turning the screws in far enough. Preferably the cap screws have lock nuts threaded on them to enable the screws tobe secured in positions projecting into the sockets 24 just far enough to provide smooth pivotal connections between the opposite sides of the pan and the adjacent side wall portions of the drum.

With the pan 19 thus pivotally connected with the drum, the mouth of the drum is tightly closed by a cover 26 that is bolted or otherwise secured to a rim 27 encircling the mouth of the drum.

If ordinary care is exercised in filling the pan 19 with the powdered material, and in inserting it into the drum, these operations can be performed without creating a dusty environment. It is of course understood that the materials with which the powdered material is 'to be mixed are introduced into the drum before the powder filled pan is assembled therewith, so that upon securement of the cover over the mouth of the drum, the apparatus is all set to effect the desired admixture. As soon as mixing rotation of the drum commences,

the pivotally supported pan will swing about the common axis of its pivotal connections with the drum, spilling the powdered material onto and into the other material in the closed drum to become thoroughly admixed therewith without creating the objectionable dusty environment that was so characteristic of all prior ways of handling the admixture of dry powdered material with other dry ingredients. Although the specific structure of the parallel tracks 22 is a matter of choice, a convenient way of construct ing them resides in cutting slots through the cylindrical wall 17 and welding channels 28 over those slots; and to provide adequate length for the tapped holes 29 into which the cap screws are threaded, pads 30 are welded to the web of the channel atthe inner ends thereof, the tapped holes passing through the pads as well as the web of the channel.-

Those skilled in the art willappreciate that the invention can be embodied in forms other than as herein disclosed for purposes of illustration.

The invention is defined by the following claims:

1. In a mixing apparatus including a mixing drum having a mouth which is the only opening into the drum and through which different materials to be mixed may be piaced in the drum and the resulting mixture discharged from the drum, and means for imparting motion to the drum to thereby effect admixture of the materials in the drum, the improvement whereby very fine powdered materials may be admixed with other material without creating an objectionable dusty condition, and which improvement comprises:

A. a pan of a size to be passed through the mouth of the drum while the pan is in an upright position containing the fine powdered material;

B. cooperating pivot means on the pan and in the drum to support the pan in the drum in a manner permitting the pan to tilt and spill its contents into the drum for admixture with other material therein as mixing motion is imparted to the drum;

C. a cover to close the mouth of the drum; and

D. means for securing'the cover in place closing the mouth of the drum.

2. Mixing apparatus of the character described comprising the combination of A. a mixing drum mounted for rotation about its axis and movable to and from a position in which its axis is substantially horizontal, the drum having as its only opening a mouth at one-axial end thereof through which materials to be mixed are introduced intothe drum and the resultingmixture discharged from the drum;

B. a pan of a size to be passed through the mouth of the drum with the pan in an upright position and filled with material to be admixed with other material in the drum;

C. cooperating supportmeans on the pan and in the drum to support the pan in its upright position during insertion of the pan into the drum while the drum is in a position with its axis substantially horizontal;

1). means for constraining the pan after its insertion into the drum against all motion thereof with respect to the drum except revolution about an axis fixed with respect to the drum and so located that rotation of the drum causes the pan to revolve and spill its contents into the drum; and

E. a cover removably secured across the mouth of the drum.

,3. The mixing apparatus of claim 2, further characterized in that:

A. said pan has bottom and side walls; and

B. said cooperating support means comprises 1. protuberances projecting from opposite side walls of the pan, and

2. track means fixed inside the drum and substantially parallel with the drum axis to slidably receive said protuberances.

,4. The mixing apparatus of claim 3, wherein said means for constraining the pan to said revolution comprises a pair of coaxial pins mounted in opposite walls of the drum for axial movement towards and from one another, said coaxial pins having end portions projectable into sockets that are fixed with respect to the side walls of the pan.

5. The mixing apparatus of claim 4 wherein said sockets are in said protuberances; and wherein abutment means in the drum are 'engageable by said protuberances to limit insertion of the pan into the drum, said tracks and abutment means being so located with respect to said coaxial pins that the sockets in the protuberances are in line with said pins when the protuberances engage the abutment means.

6. The mixing apparatus of'claim 5, wherein said coaxial pins are pointed screws threaded into coaxial tapped holes through the wall of the drum.

7. The mixing apparatus of claim 2, wherein said pan has side walls and wherein said means for constraining the pan against motion other than said revolution thereof comprises a pair of coaxial pins mounted in opposite walls of the drumfor axial movement towards and from one another, said coaxial pins having end portions projectable into sockets that are fixed with respect to the side walls of the pan.

8. Mixing apparatus of the character described comprising:

A. a mixing drum having a charging and discharging mouth defined by a substantially cylindrical wall;

B. means defining a pair of inwardly opening parallel grooves in diametrically opposite portions of said substantially cylindrical wall;

C. a pan having bottom and side walls;

D. a pair of coaxial outwardly projecting bosses on opposite side wall portions of the pan, the pan being of a size to be received in the charging and discharging mouth of the drum with its bosses slidably engaged in said grooves;

E. abutment means to limit insertion of the pan into the charging and discharging mouth of the drum and to define a position of the pan in which no portion thereof protrudes from said mouth; 7

F. cooperating means on the pan and the mixing drum to hold the pan in said defined position against all motion with respect to the drum other than revolution of the pan about the common axis of said coaxial bosses;- and G. a cover removably secured across the mouth of the drum.

9. The method of dry mixing fine powdered material with other material, which comprises:

A. placing said other material in a mixing drum;

B. placing the fine powdered material in a pan having side walls;

C. carefully inserting the filled pan without disturbing the fine powdered material therein completely into the drum, through its mouth;

D. without'agitating the filled pan, effecting pivot connections between the mixing drum and opposite side walls of the pan;

E. tightly closing the mouth .of the drum; and

F. imparting mixing motion to the drum to thereby cause the pan to rock about its pivot connections with the drum and spill its contents into the material in the drum and effect admixture of the drum contents. 

1. 4In a mixing apparatus including a mixing drum having a mouth which is the only opening into the drum and through which different materials to be mixed may be placed in the drum and the resulting mixture discharged from the drum, and means for imparting motion to the drum to thereby effect admixture of the materials in the drum, the improvement whereby very fine powdered materials may be admixed with other material without creating an objectionable dusty condition, and which improvement comprises: A. a pan of a size to be passed through the mouth of the drum while the pan is in an upright position containing the fine powdered material; B. cooperating pivot means on the pan and in the drum to support the pan in the drum in a manner permitting the pan to tilt and spill its contents into the drum for admixture with other material therein as mixing motion is imparted to the drum; C. a cover to close the mouth of the drum; and D. means for securing the cover in place closing the mouth of the drum.
 2. track means fixed inside the drum and substantially parallel with the drum axis to slidably receive said protuberances.
 2. Mixing apparatus of the character described comprising the combination of A. a mixing drum mounted for rotation about its axis and movable to and from a position in which its axis is substantially horizontal, the drum having as its only opening a mouth at one axial end thereof through which materials to be mixed are introduced into the drum and the resulting mixture discharged from the drum; B. a pan of a size to be passed through the mouth of the drum with the pan in an upright position and filled with material to be admixed with other material in the drum; C. cooperating support means on the pan and in the drum to support the pan in its upright position during insertion of the pan into the drum while the drum is in a position with its axis substantially horizontal; D. means for constraining the pan after its insertion into the drum against all motion thereof with respect to the drum except revolution about an axis fixed with respect to the drum and so located that rotation of the drum causes the pan to revolve and spill its contents into the drum; and E. a cover removably secured across the mouth of the drum.
 3. The mixing apparatus of claim 2, further characterized in that: A. said pan has bottom and side walls; and B. said cooperating support means comprises
 4. The mixing apparatus of claim 3, wherein said means for constraining the pan to said revolution comprises a pair of coaxial pins mounted in opposite walls of the drum for axial movement towards and from one another, said coaxial pins having end portions projectable into sockets that are fixed with respect to the side walls of the pan.
 5. The mixing apparatus of claim 4 wherein said sockets are in said protuberances; and wherein abutment means in the drum are engageable by said protuberances to limit insertion of the pan into the drum, said tracks and abutment means being so located with respect to said coaxial pins that the sockets in the protuberances are in line with said pins when the protuberances engage the abutment means.
 6. The mixing apparatus of claim 5, wherein said coaxial pins are pointed screws threaded into coaxial tapped holes through the wall of the drum.
 7. The mixing apparatus of claim 2, wherein said pan has side walls and wherein said means for constraining the pan against motion other than said revolution thereof comprises a pair of coaxial pins mounted in opposite walls of the drum for axial movement towards and from one another, said coaxial pins having end portions projectable into sockets that are fixed with respect to the side walls of the pan.
 8. Mixing apparatus of the character described comprising: A. a mixing drum having a charging and discharging mouth defined by A substantially cylindrical wall; B. means defining a pair of inwardly opening parallel grooves in diametrically opposite portions of said substantially cylindrical wall; C. a pan having bottom and side walls; D. a pair of coaxial outwardly projecting bosses on opposite side wall portions of the pan, the pan being of a size to be received in the charging and discharging mouth of the drum with its bosses slidably engaged in said grooves; E. abutment means to limit insertion of the pan into the charging and discharging mouth of the drum and to define a position of the pan in which no portion thereof protrudes from said mouth; F. cooperating means on the pan and the mixing drum to hold the pan in said defined position against all motion with respect to the drum other than revolution of the pan about the common axis of said coaxial bosses; and G. a cover removably secured across the mouth of the drum.
 9. The method of dry mixing fine powdered material with other material, which comprises: A. placing said other material in a mixing drum; B. placing the fine powdered material in a pan having side walls; C. carefully inserting the filled pan without disturbing the fine powdered material therein completely into the drum, through its mouth; D. without agitating the filled pan, effecting pivot connections between the mixing drum and opposite side walls of the pan; E. tightly closing the mouth of the drum; and F. imparting mixing motion to the drum to thereby cause the pan to rock about its pivot connections with the drum and spill its contents into the material in the drum and effect admixture of the drum contents. 